1. Field of Invention
This invention relates to devices to repair temporarily leaks in tanks. More specifically, this invention relates to an electromagnetic patch for use in the temporary repair of small leaks in tanks, particularly railroad car tanks.
2. Prior Art
Tanks containing chemical fluids sometime develop leaks caused by corrosion within the tank, the action of a corrosive chemical within the tank or as a result of an accident. Tanks used with railroad cars are sometimes used to transport chemicals which may be corrosive or even dangerous. On occasion as a result of accidents or merely as a result of corrosion, leaks develop within these tanks. These leaks may merely be a minor problem if the fluid within the tank is non-corrosive and not dangerous. However, on occasion the chemicals contained within these tanks are highly corrosive and/or highly dangerous.
The usual procedure for the repair of such tanks is to weld a new plate over the leak. However, this procedure requires the use of welding equipment which may be not only dangerous but impractical because of where the leak develops in the tank. In addition, significant delays may occur because of an inability to staunch the flow of chemicals contained within the tank.
Normally when a leak occurs, the repair first requires the emptying of the tank, followed by its permanent repair. While the tank is being emptied, the chemical may, and often does, continue to leak unless some seal is placed over the leak. In addition, sometimes drainage of the tank is delayed because of the location of the leak in the tank or the location of the tank itself. One method sometimes used temporarily to prevent leakage from a tank is to place a patch over the leak and apply bands around the tank to hold the patch firmly in place against the leak. This method is awkward, particularly where the tank situated in an inaccessible location. Furthermore, it is difficult for a serviceman to place a band around the tank and clamp it in place while holding the patch in the precise location necessary to prevent further leakage. Further, this procedure exposes the holder of the patch to the contents of the chemical spill.
Temporary seals for chemical leaks which use a magnet as an element of the seal have been disclosed, for example, in U.S. Pat. No. 2,727,650. In that device a block comprised of a synthetic rubber, such as neoprene, is placed against a leak. The resilient block is cemented to a bar magnet. Blocks of steel are also secured to the bar magnet on either side of the resilient block. The magnetism of the magnet transfers through those steel blocks to hold the patch in place against the
A similar magnetic tank repair device is disclosed in U.S. Pat. No. 3,251,461. This device is comprised of a bar magnet or magnets which are attached to a patch which can be formed into a shape to fit onto a tank. Generally the patch is a non-magnetic material which may be compressible or rubber-like. This patent attempts to solve the same problems disclosed in U.S. Pat. No. 2,727,650 . To solve these problems it relies on a bar magnet placed close to the surface of the tank to hold a patch in place.
While both of these patents disclose devices which may be useful in certain circumstances, there are certain problems which are not solved by these patents. Bar magnets, if large enough to provide sufficient holding power, are frequently awkward to handle. If not of sufficient holding power, they may not be adequate to place the required pressure upon the leak to prevent discharge of the chemical from a tank. Because of their inherent bulkiness, it is sometimes difficult to place these devices on the tank at a precise location. In addition, once in place, they may be difficult to remove to reposition. Finally, there is no mechanism to modulate the pressure on the patch itself to increase its sealing capacity.
Therefore, it is an object of this invention to provide an electromagnetic device for the temporary patching of tanks.
It is a further object of this invention to provide a new and useful electromagnetic patch for tanks and tank cars which is adaptable for use with various sizes and shapes of tanks.
It is a still further object of this invention to provide a temporary patch for tanks wherein differing pressures may be placed on the patch portion of the invention to assure stoppage of the leak.
These and other objects and features of the present invention will become apparent to those skilled in the art from a consideration of the following detailed description, drawings and claims. The description, along with the accompanying drawings, provides a selected example of the construction of the device to illustrate the invention.